UINavigationController屏蔽滑动返回

UINavigationController默认支持滑动返回功能，要想取消掉需要设置UINavigationController的delegate，然后返回NO即可。代码如下：

- (void)viewDidLoad {
    [super viewDidLoad];
    self.interactivePopGestureRecognizer.delegate = self;
}
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
        return NO;
}